If physical control, randomization, and design features do not eliminate the differential effects of extraneous variables among treatment groups, the experiment
a. has been confounded, but causal statements are still possible
b. has been confounded, and no causal statements are possible
c. must be repeated without the presence of extraneous variables
d. loses external validity, but can still salvage internal validity
Question 2
As sample size increases, the distribution of sample means of samples of size n (when randomly selected) approaches a normal distribution is a fundamental assumption of the central-limit theorem.
Indicate whether the statement is true or false
Phenotypic effects in Drosophila larvae that have mutations in segmentation genes
Effects of introduced parasites on American chestnut trees.
Physical findings of the skin indicative of substance abuse
Cortical Control of Movement
The diminishing effects on body weight of a low-calorie diet and a high-calorie diet.
Phrenology model showing areas of the head overlaying brain regions that control different traits. I